This invention relates to foodstuff processing. More particularly, the invention relates to an apparatus and method producing a desired, target pH in a foodstuff.
Foodstuff processing systems may utilize a pH modification step as part of an overall process. The pH modification may entail adding a pH modifying material to a foodstuff and then mixing the foodstuff and pH modifying material to produce a pH-modified foodstuff. U.S. Pat. No. 5,871,795, for example, discloses an apparatus and method for adding ammonia to a foodstuff to increase in the pH of the foodstuff. It is also possible to modify the pH of a foodstuff by adding a pH reducing material to the foodstuff. Carbon dioxide may serve as a pH reducing material for certain foodstuffs.
U.S. patent application Ser. No. 09/286,699 entitled xe2x80x9cAPPARATUS FOR TREATING AMMONIATED MEATS,xe2x80x9d now U.S. Pat. No. 6,142,067, shows an apparatus and method for treating ammoniated meats, that is, meats which have been exposed to ammonia. The apparatus disclosed in this patent includes an ammonia contactor and a mixing arrangement. Ammonia is added to an initial foodstuff in the contactor and then distributed throughout the foodstuff in the mixing arrangement. This combination of ammonia contactor and mixing arrangement produces a foodstuff having a generally uniform increased pH throughout the material.
The foodstuff pH modification shown in U.S. patent application Ser. No. 09/286,699 must be carefully controlled to produce the desired result. Over modifying the pH in the foodstuff may affect the taste or other qualities of the foodstuff. On the other hand, insufficient pH change in the foodstuff may diminish the effectiveness of the overall foodstuff processing system.
It is an object of the invention to provide an apparatus and method for modifying the pH of a foodstuff. More particularly, it is an object of the invention to provide a pH modifying method which facilitates improved pH control. Another object of the invention is to provide a pH modifying apparatus with improved pH control capability.
The method according to the invention includes providing a first foodstuff at a first pH and a second foodstuff at a second pH. The first pH and second pH are both related to a third or target pH for the foodstuff. More particularly, the first pH is either higher or lower than the target pH while the second pH bears the opposite relation to the target pH. For example, where the first pH is higher than the target pH, the second pH is lower than the target pH. Alternatively, where the first pH is lower than the target pH, the second pH is higher than the target pH. The method includes combining the first foodstuff with the second foodstuff in a proportion to produce a combined or third foodstuff at the target pH.
The proportion at which the first foodstuff and second foodstuff is combined is determined by the values of the first pH and second pH. The first and second pH are sensed or otherwise determined, preferably on a continuous basis, and then these pH values are used to determine the proportion at which the first foodstuff and second foodstuff are combined and mixed. For example, the first foodstuff may comprise the foodstuff to which a pH modifying material such as ammonia has been added. The pH modification can be loosely controlled to produce an over modification in the first foodstuff and then the second foodstuff may be combined with the first foodstuff according to the invention to produce a combined foodstuff having the target pH.
The method according to the invention may be performed in a continuous or batch process. In continuous processes, the invention is particularly advantageous because it facilitates improved control over the pH modification, and a means for moderating an over modified pH without interrupting the continuous process. The present method of modifying pH is helpful in a batch process in that it allows a component in a mixed foodstuff to be used to produce a more desirable pH in the mixed foodstuff.
An apparatus according to the invention includes an initial foodstuff supply arrangement and a pH modifying arrangement. The initial foodstuff supply arrangement provides an initial foodstuff to the pH modifying arrangement. A pH modifying material is then added to the initial foodstuff in the pH modifying arrangement, and the foodstuff is mixed to produce a uniform, pH-modified foodstuff. This pH-modified foodstuff may comprise the first foodstuff described above and set out in the following claims.
The apparatus according to the invention also includes a second foodstuff supply arrangement and a combining arrangement. The second foodstuff supply arrangement provides the second foodstuff, which may, for example, comprise a foodstuff in which the pH has not been modified by the addition of a pH modifying material. In any case, the combining arrangement combines the pH-modified foodstuff with the second foodstuff in the proportion required to produce the third foodstuff having the target pH. This combined foodstuff is preferably mixed together thoroughly with a suitable mixing device to ensure a uniform pH throughout the material.
The pH of the pH-modified foodstuff may be sensed or otherwise determined downstream from the pH modifying arrangement and the sensed pH may be used to control a flow rate of one or both the first and second foodstuff into the combining arrangement. Also, the sensed pH may be used to control the addition of pH modifying material in the pH modifying arrangement.
The apparatus and method according to the invention provide an important control function for continuous processes which utilize a pH modifying step. Although it may be difficult or undesirable to precisely control the pH modification by addition of a pH modifying material, the invention compensates by allowing precise control over the proportion at which the two foodstuff streams are combined. Furthermore, the apparatus and method according to the invention may provide benefits in the way the target pH is obtained. In particular, a pH modifying step in a foodstuff processing system may be more effective by first over modifying the pH of a foodstuff and then bringing the pH back to a target pH level. Also, the invention allows an untreated foodstuff to obtain the benefit of a pH modification without having to add pH modifying material directly to the foodstuff.
These and other objects, advantages, and features of the invention will be apparent from the following description of the preferred embodiments, considered along with the accompanying drawings.